Allelopathic Effect of Lamiaceous Weeds on Seed Germination and Early Growth of Aromatic Rice (Oryza sativa ‘Gobindobhog’)

Satyajit Oraon,Subrata Mondal,Piotr Sugier

doi:10.5586/aa.741

Abstract

Abstract The present study reveals the allelopathic effect of aqueous leaf and root extracts of Hyptis suaveolens (L.) Poit. and Leucas cephalotes (Roth) Spreng. on seed germination and early growth of Oryza sativa ‘Gobindobhog.’ Leaf and root extracts at different concentrations (0.5%, 1%, 2.5%, 4%, and 5%) were used to study the effect in laboratory-based experiments. After 5 days of incubation, seed germination and root and shoot length of rice seedlings were measured, and both H. suaveolens and L. cephalotes showed allelopathic effects on seed germination and growth parameters. Hyptis suaveolens showed a more pronounced effect at 5% concentration of aqueous leaf and root extracts than L. cephalotes . The inhibitory effects were as follows: root length > seed germination > shoot length. Both H. suaveolens and L. cephalotes impede seed germination and early growth of rice by releasing water-soluble allelochemicals from their leaves and roots.

Highlights

IntroductionAllelopathy is the phenomenon by which plants release chemical compounds into the environment that positively or negatively affect the growth and population of neighboring plants through various processes (leaching, root exudation, volatilization, residue decomposition, etc.) (Koocheki et al, 2013; Rice, 1984)
Allelopathy is the phenomenon by which plants release chemical compounds into the environment that positively or negatively affect the growth and population of neighboring plants through various processes (Koocheki et al, 2013; Rice, 1984)
Seed germination was inhibited in all treatments, and a significant reduction in values (p < 0.01) was recorded for percentage seed germination at all concentrations of leaf and root extracts, except for 0.5% of aqueous root extracts (p < 0.05; Table 1), with germination declining progressively with increasing concentrations of aqueous leaf and root extracts

Summary

Introduction

Allelopathy is the phenomenon by which plants release chemical compounds into the environment that positively or negatively affect the growth and population of neighboring plants through various processes (leaching, root exudation, volatilization, residue decomposition, etc.) (Koocheki et al, 2013; Rice, 1984). Hyptis suaveolens (pignut; Lamiaceae) is an annual herb and, because of its rapid rate of emergence, this invasive weed has negative effects on native plant communities and impedes the growth of vulnerable or threatened species (Padalia et al, 2014). (guma; Lamiaceae) is an annual herb that generally grows in the rainy season and is commonly found by the roadside and in wasteland and fields (Chauhan, 1999; Khanam & Hasan, 2005). E aim of the present investigation was to study the allelopathic potential of aqueous root and leaf extracts of H. suaveolens and L. cephalotes on seed germination and early growth of the economically important aromatic Oryza sativa cultivar ‘Gobindobhog.’

Plant Material

Preparation of Aqueous Leaf and Root Extracts

Bioassay

Statistical Analysis

Results

Discussion